Oh man, Retrouvailles.
I listen to Rachmaninoff's recordings whenever I need inspiration from a pianist in absolute control over his art. It would sound absurd if I was describing an artist other than Rachmaninoff, but for me his pianism emanates a noble soul and the finest aspects of the human spirit.
Just listen to his Chopin B flat minor sonata, his Carnaval, Gnomenreigen, Schubert Song transcription, Rach Rhapsody (--my favorite of his performances of his own compositions, but his other concerti performances are also stellar).
I just don't think Rachmaninoff can be rated highly enough. For me one of the greatest composers and one of the greatest pianists of all.